EOS is a Java component which implements OCL2.0 evaluation on model scenarios. As a component, EOS can be used by other modeling tools to provide support for the different usages of OCL, including validating, analizing, auditing, or measuring models. The EOS's API provides, in particular, methods to insert elements, one-by-one, into models and model scenarios, and to input OCL expressions as strings of ASCII characters. In the near future, we plan to provides methods to load model and model scenarios directly from XMI files as well. The latest version of EOS is available here.